534 PHILOSOPHICAL TRANSACTIONS. [aNNO 1721. 



thing to this account, but only, that Aug. 30, before, I saw at the same place, 

 Rutland, a remarkable halo, whose upper part had its inverted arc reddish with- 

 in, and pale without, but brighter and more vivid than ever I saw before. That 

 we had there, Sept. 11, in the evening, the lightest and most remarkable 

 aurora borealis, with its unaccountable motions and removals, that ever I saw ; 

 excepting that original one, March 6, 17 J^-: that it was seen in Northampton- 

 shire, at the Bath, and elsewhere : that the vertex of the columns which shot 

 upwards, was not our vertex, but evidently 1 5 or 20 degrees distant towards the 

 south ; and that the wind was in Rutland north, as I observed myself; at the 

 Bath west ; and in Northamptonshire south ; all at the same time, which de- 

 serves particular reflection. But if any reader expects here the solution of all 

 these phaenomena, he is to know, that as to these northern lights. Dr. Halley 

 has communicated his thoughts to the public in the Philosophical Transactions 

 soon after the first appearance ; and I communicated mine about the same time 

 in a small pamphlet. And as to the halos, mock-suns, inverted arcs of rain- 

 bows, and other phaenomena of the like nature, Mons. Huygens has most 

 accurately explained them in his Posthumous Works, from p. 2^3 to p. 366 ; 

 and Sir Isaac Newton himself has touched upon them in his Optics, 1st edit, 

 p. 134, to which the inquisitive reader may have recourse for his satisfaction. 

 Only if any inquire further, why the northern lights have of late been so 

 unusually frequent, I must declare, I am far from having satisfied myself. 



Observations on the Generation of Plants. By Patrick Blair, M. D. F.R.S. 



W 369, p. 216. 



What I advanced in my Botanic Essays is now so fully confirmed by experi- 

 ments made by some curious gardeners, among whom is Mr. Philip Millar, 

 who writes me, Nov. 11, 1721, — 1. That in pursuance of my advice he sepa- 

 rated the male plants of the spinage from the female ; the consequence was, 

 that though the seeds swelled to the usual size, yet when he sowed it, it did 

 not grow afterwards. He searched into the seed, and found it wanted the 

 punctum vitae, which perhaps might have been the case with Mr. GeofFroy ; but 

 if not, the female embryos might have been impregnated another way, as he 

 experimented with 12 tulips, which he set by themselves about 6 or 7 yards 

 from any other, and as soon as they blew, he took out the stamina so very 

 carefully, that he scattered none of the dust, and about 2 days afterwards he 

 saw bees working on tulips, in a bed where he did not take out the stamina, 

 and when they came out, they were loaded with the dust on their bodies and 

 legs : he saw them fly into the tulips, where he had taken out the stamina, and 

 when they came out, he went and found they had left behind them sufficient 



